Final answer:
Iron is considered a plant micronutrient.
Step-by-step explanation:
B) iron
According to the given information, iron (Fe) is considered a plant micronutrient. Micronutrients are essential elements needed by plants in relatively smaller quantities than macronutrients. Other plant micronutrients include manganese (Mn), molybdenum (Mo), zinc (Zn), boron (B), and copper (Cu).